Fiber optic distributed acoustic wave detection technology is currently the most advanced fiber optic sound field recovery technology, which uses measured acoustic wave as a function of the length of an optical fiber, and can continuously measure acoustic wave information distributed along a geometric path of the optical fiber over the entire length of the optical fiber, provide means of obtaining both the spatial distribution state and time-varying information of the measured physical parameter for the industrial and research fields, and has been widely applied to the fields of smart aircrafts, smart bridges, expressways, important buildings, gas pipeline monitoring and optical cable monitoring and so on.
Currently, the fiber optic distributed acoustic wave sensing technology includes an optical fiber grating quasi-distributed sensing technology and an optical time domain reflection technology. The optical fiber grating quasi-distributed sensing technology realizes the distributed monitoring of an acoustic wave by using the reflection effect of an optical fiber grating, wherein wavelength change information of the optical fiber grating is used mainly, but traditional cascaded optical fiber gratings have low capacity and multiplexing rate. The optical time domain reflection technology performs measurement mainly using the effects, for example, Rayleigh and Brillouin effects produced by the acoustic wave disturbance of the optical fiber, but the energy of the scattered signal is very weak, which causes lower technical indexes, such as detection distance and spatial resolution, etc.